1. Technical Field
The present invention relates to an active matrix device, a method for manufacturing a switching element, an electro-optical display device, and an electronic apparatus.
2. Related Art
For example, a liquid crystal display (LCD) panel employing an active matrix driving system is provided with an active matrix device including a plurality of pixel electrodes, switching elements formed so as to respectively correspond to the pixel electrodes, wiring lines respectively coupled with the switching elements (e.g. refer to JP-A-2004-6782).
Typically, the active matrix device employs a thin film transistor (TFT) as a switching element. In such a TFT, an a-Si thin film or p-Si thin film is used for its semiconductor layer. Since such an a-Si thin film or p-Si thin film has photoconductivity, light leakage occurs when light is entered, thereby likely causing reduction of off resistance of the TFT or shift of threshold of the TFT.
In order to solve such a problem caused by light leakage, generally, a method by forming a shielding layer such as a black matrix that blocks light entering to a TFT is employed. However, when such a light shielding layer is formed, an aperture ratio of the panel is decreased, thereby reducing a light amount passing through the panel.
Therefore, an active matrix device (a backplane for an electro-optical display device) according to JP-A-2004-6782 employs a mechanical switching element instead of the TFT described above. Such a mechanical switching element does not cause light leakage. Therefore, the shielding layer is not required to be formed, thereby enhancing the aperture ratio. Further, unlike TFTs, the mechanical switching element does not cause variation in characteristics depending on a temperature, achieving excellent switching characteristics.
In the switching element according to JP-A-2004-6782,an actuator electrode is formed so as to face a cantilever. By energizing the actuator electrode, an electrostatic attraction is generated between the actuator electrode and the cantilever, so that the cantilever is displaced and comes in contact with a pixel electrode. This can make the pixel electrode and wiring be in a conductive state.
However, in the active matrix device described above, each switching element is formed on a substrate and includes the cantilever formed like a plate and having a surface parallel to a surface of the substrate. Therefore, an aperture ratio is reduced as much as an area occupied by the surface of the cantilever. Therefore, the active matrix device described above was not able to sufficiently provide an advantageous effect using a mechanical switching element (improvement of the aperture ratio).
If the area of the surface of the cantilever is reduced in order to enhance the aperture ratio, reducing the area of which the cantilever and the actuator electrode face to each other and concurrently reducing the electrostatic attraction generated therebetween. As a result, a driving voltage of the switching element is required to be increased.